Tag Archives: Unix Read-Write Access

How to move a WordPress instance from one server to another Linux server

Motivation:

You want to move a WordPress instance from one server to another to consolidate your websites to reduce cost.

Solution:

Install and use below Duplicator plugin to achieve your goal.

https://wordpress.org/plugins/duplicator/

User guide: https://snapcreek.com/duplicator/docs/quick-start/

If everything goes well for you then congratulation!

Otherwise, please review below possible problems and corresponding solutions.


Problem 1:

You don’t have a website on the new server.

Solution 1:

1. Create a new virtual host in the /etc/httpd/conf/httpd.conf

<VirtualHost *:80>
ServerName example.com
ServerAlias www.example.com
DocumentRoot "/var/www/www.example.com"
</VirtualHost>

2. Set 775 permission for /var/www/www.example.com

3. Restart httpd service

sudo systemctl restart httpd

Problem 2:

You are using Amazon Linux 2 server.

You are logged in as ec2-user.

You use WinSCP to upload files and edit configuration files.

You cannot modify /etc/httpd/conf/httpd.conf and /etc/php.ini.

Solution 2:

1 View permission settings for the file

ls -ld /etc/httpd/conf/httpd.conf

The result indicates that the file owner is root user and root group, not ec2-user.

2. View groups of a user

groups ec2-user

The result indicates that the ec2-user does not belong to root group.

3. Add a user to root group

sudo usermod -a -G root ec2-user

4. Grant Read-Write permission against a file to root group

sudo chmod g+rwx /etc/httpd/conf/httpd.conf
sudo chmod g+rwx /etc/php.ini

5. Logout and login to the server again.


Problem 3:

You are using Amazon Linux 2 server. The ZipArchive feature is missing.

Solution 3:

1. Execute below commands:

sudo amazon-linux-extras install php7.2
sudo yum install php-pear php-devel gcc libzip-devel zlib-devel
sudo pecl install zip-1.13.5 # we must specify a slightly older version due due to compatibility

2. Add “extension=zip.so” to /etc/php.ini

3. Restart the server

sudo reboot

Problem 4:

You don’t have a WordPress database on the new Linux server.

Solution 4:

Execute below MySQL commands:

CREATE USER 'username'@'localhost' IDENTIFIED BY 'password';
CREATE DATABASE `wp_database`;
GRANT ALL PRIVILEGES ON `wp_database`.* TO "username"@"localhost";
FLUSH PRIVILEGES;

Problem 5:

An database error occurs while restoring a website.

Solution 5:

1. Execute below commands to remove the website:

sudo chown -R ec2-user:apache /var/www/example.com
sudo chmod 2775 /var/www/example.com && find /var/www/example.com -type d -exec sudo chmod 2775 {} \;
find /var/www/example.com -type f -exec sudo chmod 0664 {} \;
rm -r /var/www/example.com

2. Upload the Duplicator files again, and restore the website again.


Problem 6:

No write access against /var/www/example.com is available for Duplicator.

Solution 6:

1. Execute below commands:

sudo chown -R ec2-user:apache /var/www/example.com
sudo chmod 2775 /var/www/example.com && find /var/www/example.com -type d -exec sudo chmod 2775 {} \;
find /var/www/example.com -type f -exec sudo chmod 0664 {} \;

2. Run http://example.com/installer.php again.